Assemble the necessary equipment on a sterile surface. It will include:

• A spinal needle. The ideal would be 24-25 gauge with a pencil point tip to minimise the risk of the patient developing a post-spinal headache.
• An introducer, if using a fine gauge needle as they are thin and flexible, and therefore difficult to direct accurately. A standard 19 gauge (white) disposable needle is suitable for use as an introducer.
• A 5ml syringe for the spinal anaesthetic solution.
• A 2ml syringe for local anaesthetic to be used for skin infiltration.
• A selection of needles for drawing up the local anaesthetic solutions and for infiltrating the skin.
• A gallipot with a suitable antiseptic for cleaning the skin, e.g. chlorhexidine, iodine, or methyl alcohol.
• Sterile gauze swabs for skin cleansing.
• A sticking plaster to cover the puncture site.
• The local anaesthetic to be injected intrathecally should be in a single use ampoule. Never use local anaesthetic from a multi-dose vial for intrathecal injection. Spare equipment and drugs should be readily available if needed. 

Performing the Spinal Injection

It is assumed that the patient has had the procedure fully explained, has reliable intravenous access, is in a comfortable position and that resuscitation equipment is immediately available.

• Scrub and glove up carefully.
• Check the equipment on the sterile trolley.
• Draw up the local anaesthetic to be injected intrathecally into the 5ml syringe, from the ampoule opened by your assistant. Read the label. Draw up the exact amount you intend to use, ensuring that your needle does not touch the outside of the ampoule (which is unsterile).
• Draw up the local anaesthetic to be used for skin infiltration into the 2ml syringe. Read the label.
• Clean the patient's back with the swabs and antiseptic ensuring that your gloves do not touch unsterile skin. Swab radially outwards from the proposed injection site. Discard the swab and repeat several times making sure that a sufficiently large area is cleaned. Allow the solution to dry on the skin.
• Locate a suitable interspinous space. You may have to press fairly hard to feel the spinous processes in an obese patient.
• Inject a small volume of local anaesthetic under the skin with a disposable 25-gauge needle at the proposed puncture site.
• Insert the introducer if using a 24-25 gauge needle. It should be advanced into the ligamentum flavum but care should be exercised in thin patients that an inadvertent dural puncture does not occur.
• Insert the spinal needle (through the introducer, if applicable). Ensure that the stylet is in place so that the tip of the needle does not become blocked by particles of tissue or clot. It is imperative that the needle is inserted and stays in the midline and that the bevel is directed laterally. It is angled slightly cephalad (towards the head) and slowly advanced. An increased resistance will be felt as the needle enters the ligamentum flavum, followed by a loss of resistance as the epidural space is entered. Another loss of resistance may be felt as the dura is pierced and CSF should flow from the needle when the stylet is removed. If bone is touched, the needle should be withdrawn a centimetre or so and then re-advanced in a slightly more cephalad direction again ensuring that it stays in the midline. If a 25 gauge spinal needle is being used, be prepared to wait 20-30 seconds for CSF to appear after the stylet has been withdrawn. If no CSF appears, replace the stylet and advance the needle a little further and try again.
• When CSF appears, take care not to alter the position of the spinal needle as the syringe of local anaesthetic is being attached. The needle is best immobilised by resting the back of the non-dominant hand firmly against the patient and by using the thumb and index finger to hold the hub of the needle. Be sure to attach the syringe firmly to the hub of the needle; hyperbaric solutions are viscous and resistance to injection will be high, especially through fine gauge needles. It is, therefore, easy to spill some of the local anaesthetic unless care is taken. Aspirate gently to check the needle tip is still intrathecal and then slowly inject the local anaesthetic. When the injection is complete, withdraw the spinal needle, introducer and syringe as one and apply a sticking plaster to the puncture site.